Load development/fireforming

Cowboy, got the same barrel as you did but did a 6mmremAI. I'm set up so I can load at the range so during barrel break in I can do some serious load development and velocity check. Remingtons old 40x test load for the 243 or 6mmrem using either 80 or 100gr bullets was 36/IMR3031 and that is my fireform load and that load works well for varmits. I've got another 6mmremAI that is my antelope rifle and this one will be my varmit rig. I've got afew other AI's in different calibers and for the most part don't know if it's just lucky but my fireform loads shoot real good. I tried some Varget in a 243 and wasn't impressed then tried it in a 6mmrem same thing both of those rifles have Hart barrels. I just ordered some of those Berger 88gr High BC Flat Base bullets to try. Well good luck and keep us all posted.

Cowboy,
Chronograph is a Chrony ,an old one at that [img]/ubbthreads/images/graemlins/frown.gif[/img] It does give me enough good readings to be more informed than without it . If I match the velocities it gives with listed powder wts./velocities in the manuals it is right with them ,just wont give readings all the time and also will give skyhigh readings a lot of the time.
As far as load development I just finished a ladder test with my newly fireformed cases that used RE22 powder under Sierra 107 mks.I started the ladder .3 gr. under max list of 43.5(SIERRA manual #5) then progressed to 47.6 grs. Velocities started at 2968 and went to 3250.No pressure signs , the cases miked .470( were .469 )
From 46.7 grs to 47.1 grs the bullets clumped in a group that was .570 in height at 300 yds., width of group was quite a bit more at 2.5 in. That would be where I come in [img]/ubbthreads/images/graemlins/laugh.gif[/img]
The Oehler is next on my tool list.Will try to post pic of ladder test.

If your wondering how the first shot bullseye a 300yds. on a ladder test I just stuck a targe tover the first shot [img]/ubbthreads/images/graemlins/grin.gif[/img] Shots 15,16,17 went off the page like a skyrocket with lots (2to3 inches) between them. It was about 90 degrees and mirage was pretty heavy(thats my story and I'm sticking to it [img]/ubbthreads/images/graemlins/laugh.gif[/img]) Jim

whats the deal? just want to post and run? [img]/ubbthreads/images/graemlins/crazy.gif[/img] If you knew how long it takes me to type a reply to you ........ so ashamed you would be [img]/ubbthreads/images/graemlins/laugh.gif[/img]

I actually tried this when I started playing with my 270 Allen Mag wildcat. Figured I would see how fast I could push the round in a fireforming load, basically as an experiment.

I will tell you that even in a properly headspaced rifle set up with a 0.004" crush fit on the case like my rounds and the Ackley rounds should have, you will reach a point where case head seperation will still become a problem.

The reason I believe is that the top end pressures just force out the case to violently. They just do not have time to stretch to fill out the chamber and the case will begin to seperate at the case head.

In my round, I got to 3200 fps with the 169.5 gr ULD RBBT in virgin brass when this started happening.

Also, the energy required to form the case will result in different performance once that same load is used in a formed case.

For this reason I use the lightest load that blows the shoulders out sharply and then develop loads after that. Case will last much longer that way.

Jimm - didn't mean to post and run but i've been very busy lately, its haying time and been working sun up to sundown. Your ladder test looked like it worked. How did you spot your shots to number them. Was it the video camera like abinook used or were you able to spot them with a spoting scope? How did the brass survive the top end fireforming load? Was there any that got wasted?

fiftydriver - what do you think would be enough to fireform but not too much? Would max listed for the 243 be too much for the AI? Maybe I should bump it down a little. I don't want to do a lot of experimenting if I can avoid it. I'll save the experiments for the load development.